Technical Field
This Patent Disclosure relates generally to security/alarm systems designed to detect unauthorized entry/displacement conditions, such as for detecting unauthorized opening/displacement of windows/doors/objects.
Related Art
A common approach to security/alarm systems is the use of security sensors that detect unauthorized movement of objects, such as doors/windows or assets, based on proximity detection.
A common approach to a proximity-based security/alarm system uses mechanical (reed) switch sensors in conjunction with magnet targets. A reed switch sensor is located in a relatively secure (inaccessible) location, and the magnet-target is mounted/attached to an object located in secure-proximity to the sensor, such that, for secure conditions, the magnet-target is magnetically coupled to the reed switch sensor. Security/alarm detection is based on proximity of the magnet-target to the reed-switch sensor, for example the proximity of a magnet-target mounted to a window to a reed switch sensor mounted to a window frame.
Such security/alarm approaches that rely on proximity detection of a magnet-target are susceptible to being defeated using a tamper-magnet that masquerades as the magnet-target. The tamper-magnet is placed adjacent the magnet-target, in proximity to the reed-switch sensor, providing a magnetic field detected by the reed-switch sensor as the magnetic field of the magnetic-target.